


Threshold Crossing

by fichuntie



Category: Cyborg 009 VS Devilman, Devilman (Anime & Manga), Devilman Lady
Genre: Accidental Voyeurism, Anal Fingering, Anal Sex, Demon Sex, Exhibitionism, Hentai, M/M, Tentacle Hentai, liminal space
Language: English
Status: Completed
Published: 2018-03-21
Updated: 2018-05-08
Packaged: 2019-04-06 05:54:00
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 3,501
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14050365
Author URL: https://archiveofourown.org/users/fichuntie/pseuds/fichuntie
Summary: Akira expects to protect Ryo from a demon. He doesn't expect the demon to be a tentacle creature with impure designs on Ryo.Ryo doesn't expect to get so much of what he wants from a literature review of octupii and demonology.





	1. grabby hands

**Author's Note:**

> please don't think there's non con. it will be addressed. you can refer to end notes if you want a sense of how Ryo ends up held by a tentacle hentai demon.

Akira hadn’t really known what to expect when turning up at Ryo’s apartment. He pulled out his phone again, still only seeing the warning text the security system sent out. As much as he’d steeled himself for something drastic like the water damage done to the photographer’s studio, Ryo’s apartment seemed pristinely untouchable. With increasing attacks on Akira’s family, it had made sense to protect his family and friends but Jenny’s ferocious grin seemed like more than supplemental security for Ryo’s high tech apartment. Akira rushed from his parked bike to the foyer of the building even as he tucked his phone back into his back pocket. 

The concierge hadn’t seemed worried at all when verifying Akira’s cycle spot and beckoning him up to the penthouse elevator. Still, the alert and tingling sense of dread for Ryo’s safety kept Akira tense, claws piercing through his fingertips, in the elevator as he prepared for a demon.

Akira stalked into the apartment entryway, alert, but nothing seemed amiss. No blood stains or screams.

Except.

He heard suspicious sounds of whimpering, a sound so unfamiliar it struck to Akira’s core far beyond the the first flush of arousal at Ryo’s vulnerability. No demon could be allowed to hurt Ryo, to see a side of him so unknown and protected from Akira. No demon could touch the parts of Ryo that Akira had never crossed. Akira pushed into the central room from the elevator entryway, ready to attack whatever demon had threatened the safety of Ryo. 

And stopped short, shocked.

Ryo was whimpering, making aborted noises of such an intimate nature Akira could barely match them with his glacier demeanor. But the sounds weren’t from an attack, not an attack of any conventional type used by demons. Still, as Ryo trickled such small sounds, there was no blood or pain Akira could see. Ryo was held in the center of the room, the couch pushed aside haphazardly by a writhing mass of tentacles.

The tentacles were wide black stripes winding around Ryo’s white clothes, pushing them into a disarray that revealed the flesh underneath. The hold was firm, but didn’t break Ryo’s soft flesh. Unlike most demons, there was no drooling yellow gore or shining ferocious eyes. Instead, the teeming black mass had spread a translucent sheen over the parts of Ryo the tentacles held tightly and brushed over. Tentacles held Ryo’s limbs spread eagle above the floor, a presentation to Akira’s position from the elevator. Akira could see the pushes Ryo attempted against the hold of the beast, each shift prompting a breathless grunt and a tightening of the arms holding Ryo. The tentacles looked like thick ropes of muscle, no octopus suckers but glistening flesh that spread over their captive. Ryo moved blindly because a thick band of muscle wrapped over his eyes, even as his blonde hair draped over the demon’s tentacle. 

Neither Ryo nor the demon-creature seemed to have noticed Akira’s entrance; apparently luxury apartments covered silent elevators. Both of them were caught unawares in a stalemate tableau that took away Akira’s breath. The tentacle creature didn’t seem to have eyes or even a clear head; the black mass twisted unpredictably as a deep shadow with no core. Rather, Ryo seemed the center: a middle of white and gold against darkness. So too was he the center of noise. He let out more whimpers in his struggle while the tentacles were silent as they wrapped around him. 

Akira knew he should say something. He should announce his arrival somehow. The text he’d sent off before heading over was surely unread as he could barely make out the cracked screen of Ryo’s laptop by the overturned sofa. Even devilman hearing wouldn’t catch his stalking entry into the apartment, intended to surprise an attacker. Ryo would never let Akira, let anyone, see him like this, powerless in the tight grasp of an enemy. Even facing against demons, Ryo kept his distance whether through the scope of a gun or a screen. He was implaccable, completely unlike the whining and blushing boy held by this demon, stripped even of his sight.

One of the tentacles wriggled under Ryo’s shirt, exploring under his clothes. Akira reached for him, protective hackles rising as fur sprouted over his clawed hands. Stepping further into the room, his footsteps against the marble were silent but Amon’s deep growl wasn’t.

Both the tentacles and Ryo flinched at the noise.

“Who’s there?” Ryo asked, head twisting toward the doorway even with his eyes covered.

**Notes for the Chapter:**

> [my tumblr is fichuntie](https://fichuntie.tumblr.com/)


	2. Chapter 2

**Notes for the Chapter:**

> ah this is a bit short  
> i didn't realize bc i don't do either, but today is april fool's and easter  
> [my tumblr is fichuntie](https://fichuntie.tumblr.com/)

Akira knew he should stop this. This was different than stolen views of Ryo’s chest under a translucent wet shirt at the pool. This was more intense than jealous stares at Ryo’s movements under flashing club lights. This was something Akira should put a stop to, should tear the black limbs off Ryo’s vulnerable wrists held over his head. And unlike the grabbing hands of club goers, Akira had a reason to tear them away from Ryo. Except there was a difference between watching and doing: In the space between fear for Ryo and jealousy at the demon’s touch, Akira didn’t act. In that open space between them was Amon’s fevered longing, hot panting breaths that were too loud in the room when he didn’t answer Ryo’s question. Akira watched the demon tentacles twist around Ryo’s body, pulling his clothes into a disarray. 

Akira didn’t have the excuse of anonymity. Ryo had already suspected it was him, who else could get into his penthouse? In the shifting of tentacles, the sliver of Ryo’s blue eyes were revealed by the movement of the tentacles to tangle in his blond hair. Ryo could see him standing there motionless. Ryo made another motion towards the door, fingers twitching against the hold of a tentacle wrapped around his wrists. The shadowy mass seemed to grow in the space between them, more tendrils reaching across the white floor toward Akira still in the entryway. 

The tentacles wormed under Ryo’s clothes, tearing at the resistance of his shirt and pant buttons while gleamingly stroking at the planes of his body. The tatters of his clothes fell as more detritus by the couch. Akira could catch the glisten of the tentacles and the flush brought under the fluid. Ryo’s analytical eyes looked hazy and, with each moment, less focused on the temerity of Akira not moving to help. Ryo looked hot as he lost control. Akira could feel the pull of Amon, the increasing hardness of his own dick and the supernatural swell of lust. 

“Akira, please,” Ryo panted, blushing. He’d be fever hot if Akira went over and touched him.


	3. Chapter 3

Ryo knew better than attempting to summon from a wiki page. He wasn’t stupid or ill informed. Terrified of the demons, sure. Ignorant of the fine courts of hell, maybe. But he did his research even while he felt numb with fear looking at the hoards that might be released on humanity. The summons for Amon hadn’t been the first google result, and he had pulled that summoning off successfully. The citations of his thesis hadn’t been easy, and now he had a PhD and a educational program under his helm. Ryo knew plenty, using planning and intellect to prepare for the battles against demons. So why had he rushed into this stupid mistake?

Ryo knew this wasn’t the right approach even as he’d read the permissions in Latin aloud. Not even the rush to equip humanity against the demons could explain why Ryo had rushed the summoning without warning Akira or Jenny of the experiment. Honestly, Ryo didn’t know why he’d gone ahead a scant few hours after receiving the scans of a Vatican demonology. Maybe he’d had faith in receiving a rescue like Miki had gotten without even realizing he was relying on Akira to defend him. Because when he’d felt the first bruising grasp of a demon tentacle, twisting towards him from the broken summoning circle, Ryo had flashed to this moment of Akira rushing to his side.

What Ryo didn’t understand now was why Akira was frozen in place. He’d come, exactly as Ryo had hoped and expected. His brown eyes were wide and riveted on the demon twisting around Ryo, but Akira remained unmoving. Ryo knew this wasn’t dangerous, a harmless demon that even the church described as more interested in pleasure than pain or violence. The spell wouldn’t work unless freely given, and Ryo’s acceptance of the touch of the demon was proved when the shadows swelled into the mass of grasping tendrils. Ryo knew the demon barely had two synapses to rub together between all the tentacles it liked to rub against things, but Akira didn’t know any of that. Akira, unmoving but panting in his doorway, didn’t know. Akira who was slowly hardening in his black pants, his arousal becoming obvious in the skin tight jeans. Ryo squirmed as the tentacles thickened around him, turning from black mist into strong bands under his clothes.

Ryo knows its his fault for crossing so easily into drugs and sex and the comfort of another body even if its one paid for. Ryo knows Akira thinks there’s a line they wouldn’t cross, but Ryo’s been to worse places than Sabbath and without a noble purpose. Every time he’d wanted Akira: there beside him, under him, however he could get him. He’ll let this thing thrust up into him if it means he can see Akira palm himself watching. He just needs Akira to cross over this threshold to be with him. 

“Akira, please” Ryo managed, feeling the tentacles tangle in his hair and clothes before continuing, “I need you.” 

It was hard to concentrate on Akira as the tentacles continued to shift and flex over his body. Being stripped nude, Ryo could feel a new set of tentacles wrapping over the newly exposed parts of his body. Everywhere the tentacles touched felt warm, raising his heat in waves. The Latin translation had warned of this effect. Ryo moaned, twisting his body against the roaming hold and feeling the slick of tentacles spread. He could feel the slimy probes at the vee of his thighs, opening his legs for not only their exploration but Akira’s eyes. 

Ryo slit his eyes open again, and yes, Akira was watching him, intensely, from the doorway. Akira’s hand had drifted down, mirroring the tentacles pushing against the dripping cock on his stomach. Ryo tried to close his legs, blushing at the silent attention Akira was focusing on him in places Ryo hadn’t let him see before. The tentacles tightened, more of the thick flesh wrapping around his thighs to keep him exposed even as he strained. They pushed curiously at him, mixing their own fluids with his precome, as Ryo’s muscles fell lax under their effect. 

At least the hold on his face was loose enough to let him turn his face to the side, breaking the tense look at Akira. It was almost worse to look down at his own body, flushed and wanting. From the corner of his eyes he could still see Akira, looking from the doorway and stuck between his devilman and human forms. He felt Akira’s eyes on him, hotter than the tentacles and more intimate.

“Did you do this? Do it on purpose? Just so I’d see you filthy like this, right in front of your door, and dripping for me?” Akira asked. 

Maybe it was Ryo’s purpose. But its not his fault Akira won’t cross over to one side or another, to touch him, slide his fingers into the places that the demon has opened him, to lick away the fluid that smeared over his belly and between his legs. Akira should have to do something. Even a devilman shouldn’t be able to resist what’s spread out by the incubii, and Akira’s resistance is clearly fraying with each breath he takes in of sweat and sex. There’s got to be a limit to the softness Akira holds in his heart, something Ryo can tempt him with. 

But he can’t answer Akira’s question as the tentacle stroking his face shoves into his mouth.

**Notes for the Chapter:**

> i've had life things going on. sorry this was a little delayed. if only i could do this for work, huh  
> [my tumblr is fichuntie](https://fichuntie.tumblr.com/)


	4. Chapter 4

A calculated promise to let the demon touch him, devour the heat and pleasure from him. He’d agreed even if he’d been hoping for Akira’s hands to replace the tentacles as they opened him, shoving inside his mouth and nudging between his legs.

Ryo only crossed further into the heat, nodding at Akira’s question. This was what he’d intended, willing to give up his control to the haze the pheromones could release as the tentacles twisted inside him. His agreement was broken by a moan as one of the tentacles pushed past his rim. 

“Are you full? Ryo, are you filled?”

The sensation was unfamiliar, unrestrained by a finger’s digits or a toy’s coldness, and, instead, twisted in all directions, curling within him. As it pushed deeper, he could feel the way it was eased by more fluid seeping from the thickening member.Maybe, jealously, Ryo could take Akira’s entrance and the demon continuing as proof of Akira’s desire. A twisting hope that twisted deeper than the tendril pressing against his rim, into him. Ryo jerked as the tentacle filled him, pushing into his mouth and ass. 

“Yes? You wanted me to see you. Did you hope I’d touch you too? Did you think this would feel like me?” Akira’s voice was deeper but Ryo couldn’t tell where he was speaking from. All he could focus on was the growing sensation. He was being touched, all over, even by Akira’s voice. Another tentacle pushed against his rim, drizzling liquid around his rim to make him relax. But each probing trace made him tighten reflexively. He gasped, as the tentacle inside him thrust, seeming pleased with the tightness. The thing inside him was swelling even as more thin tendrils wrapped around his waist to pull him down towards the probing core.

“Can it fill you like I would?”

Helplessly, Ryo could feel the throbbing pulse of the tentacle inside of him. The tentacle was swelling inside him, squirming deeply. Each pulse reached deeper inside him as he was pushed and pulled. The strength of the tentacles was overwhelming as the demon seemed to swell. Ryo gasped as the tentacle stroked over his tongue. Akira couldn’t hear his groans, even as Ryo could hear Akira circle around them.

Nothing could compare to Akira’s words stroking over him and filling his head.

**Notes for the Chapter:**

> for being patient! two chapters!!  
> [my tumblr is fichuntie](https://fichuntie.tumblr.com/)


	5. Chapter 5

Nothing could compare to Akira’s words. The sight of Akira adjusting himself in his pants as he circled behind Ryo was a close competitor, but Akira’s words came on heavy breath that brushed against Ryo’s wet skin. As he circled around Ryo, Akira’s eyes glinted yellow. 

“Ryo, baby, cross over for me.” 

But Ryo couldn’t move, couldn’t tell where Akira was as the demon held him tightly. Ryo gasped, fingers twitching against the hold. The hold of the tentacles around his wrists was strong, squeezing. He could do nothing but listen to Akira’s voice as the tentacles pulled him towards their core, thrusting into him. Akira had never held him down like this, always bending to Ryo’s will instead. Letting go, allowing the demon to take control felt different, pleasurable. 

“It’s already inside you, and you’re taking it so well” Akira murmured, and maybe, Ryo could even feel the hot breath against his shoulder, the stroke of Akira’s hand on his stomach where bands of blackness didn’t reach. He couldn’t look down as tentacles stroked possessively over his face. Only in his peripherals could he catch flashes of his own pale skin turned flushed and the hint of Akira’s tan skin over the dark lines of black. Ryo was floating, grounded only by the murmur of Akira watching him. 

Another tentacle pushed against his rim, thinner than the other, but still dripping with the warm secretions. Each brush loosened him. Another set twisted between his legs, sliding between his thighs to open them. He wanted to show Akira. Ryo tightened, relaxed, tightened as the tentacles spread his cheeks open. Could Akira see the thrusting thing inside him? His own twitching hole? The second probe pushed inside, carefully twisting against the other. Ryo groaned at the pressure. 

“Relax for me, Ryo.”

The two of them, inside him, brushed against his prostate, leaving him continuously stimulated. His gaze at the apartment door was hazy as the fullness of the stretch overwhelmed his senses. Ryo moaned, helplessly, but the sounds were caught on the tentacle in his mouth, twisting against his palate. With the dribble of saliva, Ryo could feel each thrust into his mouth. Ryo felt more fluid drip down his throat as the other tentacles continued to probe around his face, stroking the stretch of his lips around a tentacle. He could feel the brush of his own golden hair, now curling with sweat as his head turned towards the shifting sound of Akira observing him. Ryo could feel his own cock pulse, precome mixing with the demon’s fluids. 

“Would a devilman fuck you harder?” Akira had to be touching him. The dry heat against his throat was different, surely. Ryo twisted towards Akira’s voice, exposing his throat, showing the push of the tentacle against his cheek. He could feel Akira’s fingers stroke towards his collar bone, brushing against his damp skin and the glistening tentacles around his chest. A finger tweaked his nipple. At his shuddering response, the restraining tentacles twisted higher over his stomach. He was so sensitive, and the constricting black bands anchored him. Jealous, Akira dragged his hand lower, stroking against Ryo’s taunt stomach. 

“You’d take me so good, wouldn’t you? Show me,” Akira growled. 

The tentacles thrust, rhythmically, into Ryo. Unrelenting, the two felt as if they were thickening, stretching him open with each motion. The ache of it was almost too much, but Ryo could hold out for Akira’s approval. He could almost feel Akira’s hands moving over his flank, encouraging him. Ryo’s lashes fluttered at the ghost of sensation. Heat flowed over him. 

Ryo nodded helplessly. The tentacles inside of him pulsed, in his mouth, in his body. The tendrils wrapped around his waist pulled him back. It was too much, too filthy. He was trembling, overwhelmed. Akira pulled Ryo back on the demon’s pulsing core. Of course, he’d be good, spread out for Akira in the middle of his apartment. He’d take what Akira gave him, the stretch of two tendrils bigger than a cock inside him and buried so deep both rubbed against his prostate. He’d take Akira anywhere, accommodate him like he’d opened for the thrusts of the demon inside of him. 

Ryo could feel the build of pleasure and heat. The demon pulled out of him, and Ryo was too empty. Then it was back, both of the wide tentacles opening him up, and he could hear the gasp as Akira saw him take the tentacles deeper. The stretch, the pressure, the roaring filth was too much. His cock was throbbing as he tried to thrust into the hold of the tentacles. The black bands pulled him back, but the tension of his muscles brought his pleasure higher. When Ryo looked down, he thought he could see the push of them inside his taut stomach, bracketed by the hold of dozens of tentacles around his torso and legs. The two of them inside him were growing, using him deeply in places Akira’s voice reached him. He was so close, so close to Akira whose hair brushed against his cheek. Akira could see him like this. 

“Come for me. Show me how good it feels.”

The tentacles finally pushed fluid, waves of it, into Ryo as a climax that overwhelmed Ryo. Ryo melted, gasped as the tentacle in his mouth pressed against his open mouth. His cock twitched, spurting over him as the tentacles wrapped around his cock, bringing him more floating pleasure. Akira’s hand brushed against the tip of his cock as his come splattered over his own stomach and Akira’s fingers. 

 

**

Akira rushed forward to grab Ryo as the tentacles withdrew. Ryo was limp in his hold, but nuzzled against his wrist as he held him up. Akira could see the flow of fluid out of Ryo. Too much for him to hold in. Akira watched pearly fluid pushed out of Ryo’s ass as the gasping blonde reflexively clamped around the tentacle. With one hand, Akira righted the couch to settle the two of them. Distracted by the sensation of drying from Ryo’s softened skin, Akira missed the disappiration of the demon. The satisfied tentacles folded into themselves until the shadow was shrunk into nothingness.

Ryo seemed to be more aware of himself, his fevered skin cooling without the spread of new slick on his skin. Akira tilted Ryo’s head up, checking the clearness of his eyes. Sleepily, Ryo blinked back at him.

Rousing the energy, Ryo supported himself.

“So the security alert works.”

**Notes for the Chapter:**

> [my tumblr is fichuntie](https://fichuntie.tumblr.com/)

**Author's Note:**

> I'd like to make clear at the start that Ryo doesn't get in over his head. Let's consider: Ryo likes summoning demons. Ryo is a creepy professor. Octupii exist. Incubii exist. hmm, maybe Ryo's version of hands on research is a little past the responsible conduct for experimentation but very very willingly entered. Weirder hobbies exist in canon, i guess.


End file.
